Explain the benefits of traffic signals in reducing accidents and reducing time caused by jam

I just need a PowerPoint on the history of traffic signals with these four main points:<br /> 1- introduction on traffic signal (What is it?)<br /> 2-History of traffic signals ( who first invented it?, where it was invented and implemented?, why it was invented? and what did it look like? )<br /> 3-the main stages of improvements that traffic signals went through till this day ( it started as gas powered technology– electric with only two signals and four sides- then 3 signals in each intersection)<br /> 4-The benefits of traffic signals in reducing accidents and reducing time caused by jam<br /> 5- Summary slide of all the information talked about